Electric-arc lamp



(No Model.) 4 Sheets-Sheet 1".

S. E. NUTTING. ELECTRIC ARG LAMP,

No. 559,863. Patented May 12, 1896.

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S. E. NUTTING. BLBGTRIG ARG LAMP.

No. 559,863. `Patented May 12, 1896.

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@No Model.) 4`Sheets-Sheet 3` S. B. NUTTINGf.

ELECTRIC ARG LAMP.

No. 559,863. Patented May 12, 1896.

(No Model.) r 4 sheets-Sheer 4. 'S. E. NUTTING. ELECTRIC ARG LAMP.

Patented Ma 2, 1896.

midi/M52? .PHUTD-UTHUWASHIN GTDNJT C UNITED STATES PATENT OFFICE.

SAMUEL E. NUTTING, OF OI'IIOAGO, ILLINOIS.

ELECTRIC-ARC LAMP.

SPECIFICATION forming part of Letters Patent No. 559,863, dated May 12,1896.

Application filed October 18, 1898. Renewed October 14, 1895. Serial No.565,672. (No model.)

To @ZZ whom, it' nza/y concern.-

Be it known that I, SAMUEL E. NUTTING, a citizen of the United States,residing at Ohicago, Illinois, have invented certain new and usefulImprovements in Electric-Arc Lamps, of which the following is aspecification.

The object of my improvements has more especial reference to theperfecting of arelamps in which a constant-potential circuit isemployed; and my invention consists in ihe features and details ofconstruction hereinafter described and claimed.

In the drawings, Figure l is a front elevation of myimproved arc-lampFig. 2, a front elevation of a vertical section of the lower portion ofthe lamp; Fig. 3, a front elevation of the upper portion of the lampwith the casing removed and a portion broken away; Fig. 4, a frontelevation of the devices employed for regulating the amount of currentthat shall pass through the shunting-circuit, hereinafter described;Fig. 5, a front elevation of a vertical section of a portion of theupper end of the lamp-frame with some of the parts in place, taken inline 5 of Fig. G Fig. a plan view taken in line G of Fig. 5, viewed frombelow; Fig. 7, a section taken in line 7 of Fig. G, and Fig. S adiagrammatic view showing the circuits.

In the description of my arc-lamp I shall describe particularly onlythose things which are intended to be the subject of claims and give buta general description as to the other parts, as for the purposes of thiscase I deem it unnecessary to describe minutely all of the partsrepresented in the drawings. In describing an arc-lamp in which aconstant-potential circuit is employed, embodying my improvements Ishall begin with th ebottom portion of the lamp and proceed to the otherparts in their order.

I inclose the arc-drawing magnet Ain a tube or case A. The arc-drawingmagnet is coiled around a spool or thimble CL, which is provided with anenlarged head at its bottom ct. At the lower end of the case is arrangeda dash-pot A2, provided with a piston a?, resting on the coiled springA3, which tends to lift the piston, with its piston-rod ai, to thehighest limit allowed. rIhe core of the magnet I3 terminates in acarbon-holder l), in which the lower carbon is held in place. I arrangeon the core a cap I5', which surrounds the top of the case A and servesas a cover to prevent dust and other foreign substances from getting in.Vhenever the current from any cause becomes weakened-as,for instance,from the presence of too great an arc, owing to the too slow feeding ofthe upper carbon-the coiled spring lifts the piston in the dash-potuntil it comes against a wire or contactpiece Z1', adapted to form aportion of a shunt-circuit around the arc, as hereinafter described.

In order to feed the upper carbon, I arrange in a case at the top of thelamp a carbonholding rod C, provided with teeth, as shown in Fig. Iarrange in proper position with reference to it a disk of softenablesubstance O. This disk is mounted on a shaft or spindle, which carries agear c, whose teeth engage with the teeth 011 the carbon-holding rod, soas to gear them together, by which I mean a connection causing them tomove in unison. A heating-pin c extends into the disk a desireddistance, so as to hold the disk from rotating under the stress of theweight of the upper-carbon holder and carbon until it has been heatedenough to melt or soften the substance of the disk, so as to melt itsway through the same. This pin is heated by the wire D of ashunt-circuit, a portion of which is coiled around the same a sufiicientnumber of tim es to insure its becoming heated by the passage of thecurrent. The wire of the shunt-circuit after leaving the pin passes intoa spring E, which in the normal operation of the lamp 'is held out by asliding rod e, on which the heating-pin is mounted. This in the normaloperation of the lamp causes the spring E to contact or rest against aspring E, which thus forms part of the circuit. The wire passes from thespring E through a number of turns F, which form the principalresistance. At different points wires f lead from the turns tocontact-points f. These contact-points are arranged so as to be broughtinto contact one at a time with a contact-arm Gr, mounted on a bent orcoiled tube G, filled with a fluid sensitive to changes in thetemperature, so as to contract or expand with them. As the bent tube iscontracted or expanded it moves into contact with one or an- IOO otherot the contact-points f', and as one or another is brought into contactwith it a greater or a less number of turns in the wire of theshunt-circuit has to be traversed by the current before it can pass fromone terminal to the other.` Oii course it will be understood that insetting the lamp the contact-arm G will be arranged in contact with theparticular contact-point f that will insure the desired amount ofcurrent through the shuntcircuit, and so that a greater or a less amountof current will be caused to pass through the shunt-circuit as thetemperature may rise or fall, thus insuring a constant feed of the uppercarbon through the maintenance of the requisite amount oi heat in theheating-pin to cause it to melt through the disk with a constant rate ofspeed whether the temperature be high or low. Then for any reason theupper-carbon holder and carbon are prevented from descending-as, forinstance, through accident or the intervention of foreign matter betweenthe teeth of the carbonrod and the gear-the heating-pin continuing tomelt the softenable substance will be moved through the same by thepressure of the spring E against the end of the sliding red on which itis mounted. This will go on until the spring E has moved away from thespring E', as shown in Fig. G, when the shunt-circuit will be opened andthe current cease to heat the pin in the disk. This protects the pinfrom becoming overheated, as well as waste of the softenable substanceforming the disk. Vhen the upper carbon fails for any reason to descendwith its proper and normal movement, the current becomes weakenedthrough the lengthening of the are. This weakens the action of theelectromagnet and permits the coiled spring A3 in the dash-pot togradually move the piston a2, carrying the lower carbon upward. Beforethe piston reaches the upper end of the dash-pot, at which time thelower carbon could be carried no higher, it comes in contact, as alreadysaid, with the contactpiece Z1. This causes a portion of the circuit topass through the wire II to the contactpoint f', which is in theshunt-circuit, with the least resistance, though it need not necessarilybe the contact-point of least resistance; but it must be one of. lessresistance than the maximum. This has the same effect as if thecontact-arm G were brought against the same contact-point, causing agreater amount of current to pass through the shuntcircuit, and thuscauses the heating of the pin in the disk to a greater extent, so thatthe disk will be more rapidly melted and the upper carbon more freelyfed downward. This again shortens the arc and causes an increase otcurrent in the electromagnet until the n ormal condition has beenrestored, when the piston a2 has been moved out of contact with thecontact-piece b and the lamp operated as before the difficulty hadoccurred.

lVhat I regard as new, and desire to secure by Letters Patent, is-

1. In constant-potential arc-la1nps,the combination of an arc-drawingmagnet, a shuntcircuit around the are, and means operated by the magnetfor varying the resistance of the shunt-circuit around the are,substantially as described.

2. In constant-potential arc-lamps,the combination of an arc-drawingmagnet, a shuntcircuit around the are, a contact-piece adapted to form apart of the shunt-circuit, and a part connected with the negative sideof the main circuit which moves against the contact-piece and brings itinto the shunt-circuit as the arc becomes lengthened and before itbreaks, whereby the resistance oit' the shunt-circuit is reduced and thefeeding of the upper carbon accelerated, substantially as described.

3. In constant-potential are-lamps,the combination of an upper-carbonholder, a disk of softenable substance geared with the carbonholder, ashunt-circuit around the are closed during the descent of thecarbon-holder, and means engaging such circuit and the disk for openingthe circuit when the upper-carbon holder ceases to descend,substantially as described.

4. In constant-potential arc-lamps,the coinbination of an upper-carbonhelder, a disk of softenablc substance geared to the carbonholder, a pinelectrically heated engaging the disk, a sliding rod on which the pin ismounted, a spring forming a portion of a shunt-circuit around the arcclosed during the descent of the carbon-holder and adapted to bearagainst the end of the sliding rod and force the pin through the diskwhen the descent ol' the carbon-holder ceases until the circuit of whichthe spring forms a part is opened, substantially as described.

5. In constant-potential arc-la1nps,lhe combination of an upper-carbonholder, a disk of softenable substance geared tothe carbonholder, a pinelectrically heated engaging the disk, a shunt-circuit around the archaving a portion of its wire wound around the pin for heating it, asliding rod on which the pin is mounted, a spring forming a portion of acircuit closed during the descent of the carbon.- holder and adapted tobear against the end of the sliding rod and force the pin through thedisk when the descent of the carbon-holder ceases until the circuit ofwhich the spring forms a part is opened, substantially as described.

SAMUEL NUTr ING IVitnesses:

SAMUEL E. I-IIBBEN, THOMAS F. SHERIDAN.

IOO

